Buttonhole sewing machine



V Julie 3, 194%. 'w. E, NICHOLS V 2,421,712

BUTTONHOLE SEWING MACHINE Filed Jan. 9, 1945 I 2 Sheets-Sheet 1 bum8.1mm.

' INVEWFU June 3,1947. w. E. NICHOLS 2,421,712 I BUTTQNHOLE SEWINGMACHINE Filed Jan. 9, 1943 2 Sheets-Sheet 2- v INVE'N4'UR:

Patented June 3, 1947 Walter: ELNi-chols, Milton, Mass, assignor'to TheReece" (Corporation; a, corporation 015 Maine- 'ApplicationJ'anuary 9,1943', Serial No. 471,843

3 Claims: 1 i his inventionrclates tosewin'g machines, and especiallytobuttonhole sewing machines of the" type linown as straight hole machinessuch as those described in Patents Nos. 714,284, Novem- February 24,I914; 1,4025073", January 3; 1922 and 1,48%,3fli; February 12, 192i.

The invention. relates particularly to an; improvement in threadcutting. or trimming mech anisms; for machines of this and other typesin, 1'0

which the: trimming mechanism is operable uponthe completion of the.stitching operation to set' the final; stitch and then to cut or trimthe thread;

Buttonhole" sewing" machines of the straight hole type include a cutterfor cutting the but- 1 5* tonhole slit substantially upon the completionof" the stitching operation and another cutter operable immediatelythereafter'to severor trim the sewing"; thread; In some suchzmachine's",the butslight continued movement, usually-termed over-'- throw, andwhichis; in effect, a jolt or far given at the time when the-movingparts-became locked;

This dependence; for the operation of the thread trimmer, upon thestopping impact, overthrow, or momentum of the machine", which may'varyconsiderably 'under variable conditions, has re sulted in unreliableand: uneven trimming.

Theobject' of the present inventionis to avoid" possibility of prematureoperation-{of the thread trimmer; andinterference between the latter-andthebuttonhol'e cutter, as aforesaid; and to provide meansfor'operating'said'trimzmer with auni form, positive action;consistently and absolutely contingent upon thecutting operation andsuitsequent retraction of said: cutter,- independent of the impact ofthe stopping mechanis and urnlimited by the momentum of the machine Theinvention will best be understood from the ton-hole. cutter is" timed tooperate just prior to; fbi'1oWiI-1g-description: of an illustrativeembodi the" completion of the sewing cycle, usually during the,formation. of the last stitch, and the thread trimmer to operateimmediately upon the completion of'the last stitch and", the stopping ofment thereof shown in the accompanying draw ings.

In the-drawings:

Fig. 1 is avi'ew in sideelevation, partly insecthe machine. In many suchmachinesthe but: W311 d P broken" away"; o maighihe' tonhol'e cutter andthe threadtrimmer are obliged; to operate in intersecting or closelyadjacent paths: Normally the buttonhole cutter completes: its operationandis retracted" or raised just'prior to the operation of. the threadtrimmer, but if the button-hole cutter should for some. reason becomejammed in the work and fair to rise: promptly, there is: a: possibilityof, its being struck by the thread; trimmer with resulting damagetoeither: orbothof them.

Attempts havev heretofore been made to avoid interference of this sortby making the operation. of the thread trimmer automatically contingentupon. the retraction ot the; buttonhole cutter, as:

by" providing an operative connection, between the trimmer and itsactuating means, which is" automatically disabled or uncoupled exceptwhen the buttonhole cutter is in rctractedpositionm Even with such anarrangement, however, it is,v

the parts, for the trimmer actuating means to causea premature operationofthe trimmer when. the huttonholecutter has been moved partly out ofits fully retracted position but before completion of itsbuttonholecuttingstroke.

In machines of the straight hole type referred to; as: heretoforeconstructed, the thread? trimmer received its movement solely fromthemoment-umor the machine at thetimewhen the;

body-i'ng the prevent invention, showing theparts in the positions: theyoccupy when the thread trimmer is in operation. Fig; 2isa perspectiveviewofi the thread trim- 30 merandassociated partsl l pussible,v due t0wean roughness and sticking: 4-5 stitches along the sides oi" thebuttonhol'e.

Fig. 3 isa plan view of the machine oflif-igil, partly in sectionand'p'artly broken away.

Fig. 4' is a fragmentary viewin end elevation as viewed from the rightin Figs. 1 and 3.

The machine shown. im the drawing-si'may, as

to its general organization, be: similar to those described in thepatents above referred to: It

comprises abed M from which rises a standard lEoar-rying an overhangingarm l'fii spacedi above the bed; The work W is carriedfby at work clampor holder comprising a clamp plate FE and coopcrating clamping arms 8,said: work: holderbeing movable as a unit overrthelbaed, bymechanismgenerally indicated eel-am orderto position; the The stitch-forminginstrumanta'lities comprise an? eye pointed needle 2 ll above": the workand coopem. ating' loopers or equivalent under thread me'cha nism 'orhandling devices: 2l below the work, there being a throat plate 22carried by the bed f4 and having an opening through which theneedleoperates. The needle 20 is carriedby' a needle bar 23 which islongitudinally and verticallyreciproeated, by means generally indicated?at 2'4,

resiliency of the stopping mechanism allowed 8; 5* in a needle bar guide253 means; not shown, bee

ing provided for oscillating said needle bar guide alternately inopposite directions transversely to the direction of feed of the workclamp between successive strokes of the needle to position the depthstitches. The thread if is taken from a suitable source and passes tothe needle eye through a take-up 26 and suitable tension devices 21 and28, after which it passes through the work and throat plate to theloopers 2!. A main shaft 29 journalled in suitable bearings in the bedhas power applied thereto by a belt 30 alternatively engageable withfast and loose pulleys 3i and 32 under the control of a belt shifter 33.The belt shifter 33 constitutes an extension of a stop member or arm 34carried by an oscillating and longitudinally movable rock shaft 35mounted for oscillation and a limited longitudinal movement in the bedl4. Associated with the sliding rock shaft 35 is a spring 36 (Fig. 3)surrounding said shaft and interposed between a collar 31 and one of thebearing brackets or ears 38 in which said shaft is mounted, said springtending normally to move said shaft toward the right in Fig. 3. Slidablymounted in the stop arm 34 is a stop element or bolt 4| normally urgedtoward the right in Fig. 4 by a spring 42. At its end the bolt 41 isformed with a nose 43 which is in the path of movement of a cam 44 faston the shaft 29 when the shaft 35 is in the longitudinal position tocause the belt shifter 33 to engage the belt 30 with the loose pulley32. Cam 44 has a concentric portion a, a rise b, a notch c and a stopshoulder d, arranged to engage the nose 43 in the order named when theshaft is rotated in the direction of the arrow in Fig. 4.

A spring-pressed plunger 45 carried by the upright standard I engagesthe stop arm 34 and tends to turn said arm and the rock shaft 35 in aclockwise direction as shown in Fig. 4 to press the nose 43 against theperiphery of the cam 44' when said nose lies in the path of movement ofsaid cam. A starting lever 46 is secured to a rock shaft 41 and isnormally urged clockwise in Fig. 1 by a spring 48. One arm 49 of saidlever is connected to a treadle T, as by linkage 50, and another arm'5l'is adapted to engage the collar 31 and move the shaft 35 to the left inFig. 1 when the treadle is depressed. 7

A detent 52 is adapted to engage a notch 53 in said shaft 35 to holdsaid shaft in its left-hand positionduringa sewing operation, othermeans, (not shown) serving to automatically release said detent at thebeginning of the last stitch-forming cycle.

The buttonhole cutter 54 is carried by a lever 55 journalled on a shortstud shaft 56 supported in the bed, said lever having an arm 51 carryingat its end a sleeve 58 in which is journalled a stud 59 having at oneend a sleeve portion 66 which receives a stud 6! extending inwardly fromthe stop arm 34.

The combined stitch setting and thread trimming element 14 is guided inways in the bed I4 immediately below the throat plate 22 and between thelatter and the loopers 2| (see Fig. 2). The element 14 is provided withan opening 15 adapted to receive a stud 16 carried by an arm 1'1 fast onone end of a rock shaft 18 journalled in suitable bearings in the bed I4. At the completion of the last stitch forming cycle, and substantiallycoincidentally with the stopping of the machine, said element is movedfrom its normal retracted position shown in dotted lines in Fig. 2 intoengagement with the thread loop as Shown in the full line position inFig. 2.

another arm 64 extending into the upright into a position to engage anextension 65 of the lever 66 which carries the clamp arms l8. By movingthe finger piece 63 inwardly (to the left in Fig. 1) the clamping armsl8 may be raised against the tension of the spring 6'! to release thework. Conversely, when the .clamp closes under the infiuence of thespring 61, the arm 64 is moved upwardly and the finger piece 63 movedoutwardly (to the right'in Fig. 1). Pivoted at 68 to the arm 64 is adepending link 69 carrying a catch 10. The link 63 is normally urged bya spring H in the direction to cause the catch 10 to engage a lug 12carried by the arm 51 of the buttonhole cutter lever 55. when thebuttonhole cutter 54 rises, the arm 64 is normally drawn downwardly toopen the work clamp. The catch 70 may, however, be disengaged from thelug 12 by a trip finger 13 secured to the shaft 41. The trip finger T3is moved into a position to move the link 69 to the left (Fig. 1) andthereby disengage the catch 10 from the lug 12 when the treadle T isdepressed, so

that depression of the treadle to start the machine serves to disconnectthe clamp and the buttonhole cutting mechanisms and permit the clamp toclose.

The shaft '18 has secured thereto, at a point intermediate its ends, anarm 19 pivotally connected by a link to the arm 8| (see particularlyFig. 4) of abell crank 82 pivoted at 83 to a bracket 84 (see also Figs.1 and 3) secured as by a screw 85 to the underside of the bed M. Theother arm 86 of the bell crank 82 is pivotally connected by a link 81 tothe arm 64 of the clamp raising lever. Consequently, when the lever arm64 rises, the trimmer 14 is retracted, and when said lever arm is drawndownwardly, the trimmer is advanced into the position shown in fulllines in Fig. 2.

In operation, the operator starts the machine by depressin the treadle Tto rotate the starting lever 46 counterclockwise and move the rock shaft35 to the left in Fig. 1 to shift the belt 36 from the loose pulley 32to the fast pulley 3| and move the nose 43 out of the path of movementof the cam 44, said shaft 35 being retained in this position until thebeginning of the last stitch-forming cycle by the engagement of thedetent 52 with the notch 53. Depression of the treadle also causes thetrip finger 1,3 to disengage the catch 16 from the lug 12, therebypermitting the work clamp to close under the infiuence of the spring 61,raising the lever arm 64, and retracting the trimmer 14. The treadle isthen released, permitting the spring 48 to restore the lever 46 and tripfinger 13 to the position shown in Fig. 1. When the detent 52 iswithdrawn from the notch 53 at the beginning of the last stitch-formingcycle, the spring 36 causes the shaft 35 to move toward the right inFig. l to shift the belt 30 from the fast pulley 3| to the loose pulley32 and again bring the nose 43 into the path of movement of the cam 44.During the formation of th last stitch,'the

Consequently,

, provement of considerable advantage.

. meiiine it sunder its wn; monientumfandthe nose *43 follows thperiphery of the cam? until lever 5, tolift said arm5'l andtherebyadvance plunger 45, enters the notch "c, this movement causingf the"buttonhole cutter 54t'o be retracted or "raised-rtoits originalor'inoperative position.

,As the lever 55 is raised, the arni 51 is lowered,

andthe lug-12 eng es thecatch lfl inthe link 69 and pulls downwardlyonsaid link, whichin turn depresses the arm 64 of the clamp raisinglever 63. As the arm 64 is depressed, it operates through the link 8'!,bell crank 82, link 80 and arm 1-9 to rotate the shaft 18 clockwise inFig. 4. This rotation of the shaft 18 operates, through the arm 11 andstud 16, to advance the trimmer 14 from the position shown in dottedlines in Figs. 2 and 3 to that shown in full lines in the same figures,this movement acting to set the stitch and trim or cut the thread loop.

It will be observed that the trimmer is operated from the buttonholecutter lever during the rise, or retraction, of the cutter, and that theconnections for operating the trimmer (including the link 69, catch andlug 12) are disabled or disrupted when the machine is started and arenot restored until the cutter has descended on its cutting stroke andsubsequently rises. Therefore, the trimmer I4 cannot be prematurelyoperated; it is operated only when the buttonhole cutter 5-4 hascompleted its cuttingstroke and has been raised out of the work and isconsequently out of the pathof movement of said trimmer. The springpressed plunger 45 is the means used to raise the buttonhole cutterlever 55, and is also the source of power for actuating the trimmer 14,the arm 51 of the lever 55 and the arm 64 0f the clamp raising leverserving as a part of the system of linkage connecting the spring pressedplunger 45 and the trimmer I4.

The use of the spring-pressed plunger 45 instead of the stoppingmechanism for furnishing the power for operating the trimmer is an im-It has been found in practice that the cutting of a relatively smallbuttonhole requires less force than the cutting of a large buttonhole.If the cutting operation takes a larger proportion of the power suppliedby the momentum of the machine, it correspondingly-leaves less for theoperation of the trimming mechanism and may result in incompleteoperation, of the trimmer, and conversely, when the cutting operationrequires a small part of the force supplied by the momentum, theremaining larger force of the momentum, if it is not absorbed byreadjustment of the spring loaded plunger 45, will increase the wear andshock on the stop motion parts. If the momentum of the machine is usedto operate the trimmer, the variation in the size of the buttonhole cuttends, therefore, to cause a corresponding variation in the operation ofthe thread trimmer.

6 ""Very careful machining, smooth surfaces, frequent lubrication, i andadjustment of the spring loaded plunger to balancethe amount of momentumnecessary for trimming and stop 'ping are required if the momentum ofthe machine, acting through the stopping mechanism, is to besuccessfully used to operate the trimmer. roughness or irregularity ofthe cam 44, for instance, tendsto cause the trimmer to receiveitsimpulse simultaneously with the movement of the buttoriholecutter, and 1these v ariations in opera tion are,fof 'coursefaptto be increased astheparts begin-to wear, The utilization of thespring pressed plunger-45 asa source of power for the openness the trimming mechanism, however,provides'aeonstant, unfluctuating" force, the application-of which tothe trimming mechanism is always contingent upon the pr'oper elevationof the button hole cutter 54 due to the factthat a part of the cutter 1operating mechanism forms a I link in the chain of elements 1 connectingthe plungerandthe trimmer. i

The connection with the arm 64 of the clam raising lever also providesfor operation of the trimmer independently of the automatic operation ofthe machine. If, for instance, the operator wishes to inspect the workor remove it for any reason before the completion of a sewing operation,he can stop the machine and move the finger piece 63 inwardly to raisethe clamps and release the work. Formerly, the work was held by thethread, but in the machine of the present invention the thread istrimmed as the clamps are raised, allowing the operator to move the workfreely or remove it entirely.

I claim:

1. In a straight-hole button-hole sewing machine having a single cycleof operation during which the sewing is done and the button-hole is cutand the thread is severed, in combination, a button-hole cutter, a workclamp, clamp raising means, a thread trimmer, means operative during theformation of the last stitch to depress the button-hole cutter to cut aslit in the work,means operative thereafter to retract said button-holecutter, a releasable connection between said button-hole cutter and saidwork clamp raising means, means for releasing the connection when Idepressed, and means connecting the clamp raising means and the trimmer,said releasable connection after the button-hole cutter is depressedbeing operative during the rise of the cutterto button-hole cutter, awork clamp, clamp raising means, a thread trimmer, means operativeduring the formation of the last stitch to depress the button-holecutter to cut a slit in the work, as

the needle rises on the last up-stroke, means operative thereafter toretract said button-hole cutter, a releasable connection between saidbutton-hole cutter and said work clamp raising means, means forreleasing the connection when the machine is started, means forre-establishing the connection only when the button-hole cutter isdepressed, and means connecting the clamp raising means and the trimmer,said releasable 2&2157112 connection after the button-hole: cutter isdepressed being operativeonly =duringethe rise of the cutter to transmitforce derived from the cutter. retracting means directly tothe clampraising means and acting through said last named, means to move th e;trimmer to sever the thread. 3.111 a straight-hole button-holesewingmachine'having a single cycle of operation during which the sewingis done and the button-hole is cut and therthread-is severed, incombination; a button-hole cutter; a work clamp, clamp raising means, athread trimmer, means operative duringthe formation of the last stitchto depress the button-hole cutter to cut a slit in the Work, as theneedle rises on ,the last up-stroke, means operativepthereafter toretract said button-hole cutter; a releasable connection betweensaidbutton-hole cutter and said work clamp raising means, means forreleasing the connectionwhen the machineis started, means forre-establishing the connection only when the button-hole cutter s: deprs e a d: m ans .i onnectin vihelslamn r n m s {and h tr m said re eaable connection afterthe bu'ttpn-hole' cutter is ,de pressed beingoperative only during the last part ofthe rise: of the cutter'totransmit force: derived.

from the cutter retracting means-directly to the clamp raising meansand-acting through said last named'means to move the trimmer to-sever;

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